title: Factors associated with lymph node metastasis in radically resected rectal carcinoids: a systematic review and meta-analysis.
abstract: BACKGROUND
  Although various guidelines regarding neuroendocrine tumors were released, treatment for rectal neuroendocrine tumors with size between 1 and 2 cm has not been explicitly elucidated. The determinant factor of the choice between endoscopic resection and radical surgery is whether lymph node involvement exists.
  
  
  OBJECTIVE
  This study aims to explore factors associated with lymph node involvement in rectal neuroendocrine tumors by conducting a meta-analysis.
  
  
  METHODS
  A broad literature research of Pubmed, Embase&Medline, and The Cochrane Library was performed, and systematic review and meta-analysis about factors associated with lymph node involvement were conducted.
  
  
  RESULTS
  Seven studies were included in this meta-analysis. Tumor size > 1 cm (odds ratio (OR) 6.72, 95% confidence interval (CI) [3.23, 14.02]), depth of invasion (OR 5.06, 95% CI [2.30, 11.10]), venous invasion (OR 5.92, 95% CI [2.21, 15.87]), and central depression (OR 3.00, 95% CI [1.07, 8.43]) were significantly associated with lymph node involvement.
  
  
  CONCLUSIONS
  The available clinical evidence suggests that tumor size > 1 cm, invasion of muscularis properia, venous invasion, and central depression could be risk factors of lymph node involvement, while other factors reported by few studies need further research.
authors.affiliation: Department of General Surgery, Peking University Third Hospital, Beijing, 100191, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Zhou
authors.forename: Haiting
authors.initials: H
authors.lastname: Xie
authors.forename: Lingduo
authors.initials: L
authors.lastname: Xie
authors.forename: Jing
authors.initials: J
authors.lastname: Li
authors.forename: Wei
authors.initials: W
authors.lastname: Fu
mesh_terms: D002276:Carcinoid Tumor / Q000473:pathology* / Q000601:surgery; D006801:Humans; D008207:Lymphatic Metastasis; D015233:Models, Statistical; D009361:Neoplasm Invasiveness; D016017:Odds Ratio; D012004:Rectal Neoplasms / Q000473:pathology* / Q000601:surgery; D012007:Rectum / Q000601:surgery*; D012307:Risk Factors